Agreed. Nor does it have to be an all or nothing decision. On some of my rides, knowing the type of ride, traffic and road conditions, I may decide to wear a helmet whereas on other rides I decide not to. Same with driving - if driving in some competitive events I'd wear a helmet but using the same car to go to the neighborhood grocery store I wouldn't. I don't really get the idea that there's something so uniquely dangerous about a bicycle that I need to put on a helmet every time under every circumstance before swinging a leg over the top tube. Sure there's always the possibility that something very unusual happens even on a normally casual and safe ride (just as something could happen when driving to the store), but we base our decisions on necessary safety precautions based on our best judgement of the probability of risk, not on always imagining the worst case scenario. If we did the latter we'd never dare get out of bed in the morning.